hoses 5 yr changeout

[N223JH]

Thanks so much, gentlemen, for the info.

Jim
5 years up this month

[TS Flightlines]

One of these days when I get caught up I'll look into this. Pretty important hoses, and fairly expensive.

[Sink]

The 17mm hose on top of the engine and the two on each underside of the cylinders is made for Rotax by just one company. Unfortunately this hose has no US equivalent. I have seen some try and use use US hose sizes on this and it usually hasn't turn out well. It is a little pricey, but I would stay with it. It is sold by the meter and usually 2 meters is enough. The constant compression spring clamps are to be used with this hose 17mm only. These spring clamps will expand and contract with the heating and cooling of the aluminum fittings the hose is over. The rubber hose settles over time and it's OD can shrink just enough to leak with worm drive clamps.
The one 17mm hose on top is indeed a 90 degree preformed hose.

When replacing these hoses on top it is much easier to remove the 4 screws on each air intake manifold to allow easy access to the 90 degree fittings the hoses are on and it allows easier replacement of the hose on the expansion tank too. Don't drop anything down inside the air intake openings. I would cover them and use a flashlight to double check before putting the screws back in place. The screw torque is 90 in/lbs.


I hope this helps?

[N223JH]

Yessir, it does help. Any other tips you can share would be most appreciated. In particular, suggestions on order of disassembly for the hose changeout process and carb re-build tips.

Jim
5 years up this month

[RFSchaller]

Has anybody tried silicon automotive heater hose? At the ROTAX course the instructor said he has seen EAB engines with 5/8" heater hose and no issues. I know many don't like using non-aeronautical parts, but this would seem to be an application where the automotive and aeronautical environment are the same. Of course the consequences of failure are quite different, but the auto operating history seems to indicate automotive hoses are just as durable as the ROTAX hoses.

[Sink]

I know some don't want to hear this, but
Sometimes it's just better to stick with the proper parts and not try and save a few bucks. If you blew a hose off in flight saving $100 could cost $16.5K if you fry the engine. The least it may cost is $1.5K to get all the heads hardness tested plus the labor.
Flying = $$$ and cutting some corners can be 10-1000 times more costly in the long run.


5/8" hose will not even come close to fitting. 5/8" = 15.87mm. It won't stretch and if you forced it on you would weaken and break any internal fibers of the hose at the fitting. The spring clamps would then be too big. Anything other than the 17mm hose and the spring clamps would be useless.

11/16" = 17.46 mm
This is too big and the spring clamps absolutely won't work and the hose would leak. Then owners want to use worm drive clamps because they are cheap and you can get them from the hardware store.

If owners need to use a worm drive style clamp on a hose use a good Wurth Zebra raised rip wormdrive clamp. It doesn't cut into the hose and it won't over cam and slip. They are not costly.

If you own an SLSA in the US you can't use other clamps and hoses without Vans approval. I doubt that would be forthcoming due to the liability.

[RFSchaller]

Joe,

I understand your position, but it doesn't answer the question. Has anybody tried an alternative, and if so what was their experience with it?

Rich

[crashley]

I used silicon hoses from a truck supply 5/8 and 1" they fitted fine I used a bit longer hose where the original 90 degree bend was I also replaced most of the hose clamps with "otiker " single ear clamps on the 5/8 hoses and reused the original clamps on the 1" hoses The springs were transferred to the new hoses I had no leaks and have 10 hours on the new hoses
I used aviation hose to replace the 1/4" fuel lines and fuel injection hose for the 5/16" lines the local hydraulic shop swaged the removable hoses and I used the otiker style clamps on the other ones

[RFSchaller]

Thanks, Ashley. That's the info I wanted. A lot of folks think there is something magic about OEM parts and everything else is inferior. I think EXPERIMENTAL means experimental and we should exercise the latitude given us by law with prudence.

Rich